If you’ve created a Google+ page, Google strongly recommends linking from that page to your website and vice versa. Linking your Google+ page and your site like this not only helps you build relationships with friends and followers, but also gives Google information they can use to determine the relevancy of your site to a user query in Google Web Search. It also makes your site eligible for Google+ Direct Connect.
How to Link your Google+ page and your website
Make sure that your site’s home page is available to appear in Google’s search results and isn’t blocked by a meta noindex tag or by your robots.txt file. (Verify by doing a site:search for your domain, like this: [site:example.com]. You can also use the Fetch As Google tool to see your page exactly as Google sees it.)
Update your site’s home page by adding a link to your Google+ page, like this: yourpageID]” rel=”publisher”>Find us on Google+
To find your page URL, open your page and copy the web address from the browser address bar.
It’s best to add the link to your most significant page. Usually but not always this is your home page; for example, if you’ve created a page for a product, you can add the link to the product description page.
Link to your website from your Google+ page’s profile. To edit your page profile:
Make sure you’re on the Google+ page you’d like to edit.
Click the profile icon .
Click Edit Profile.
Click Website. You’ll know it’s editable when the color of the section changes to blue.
Type your homepage URL. This should match exactly the URL of the page to which you added your Google+ page link in step 1.
Use the rich snippets testing tool to check your markup and make sure that Google can extract your page information from your content. This tool will display the markup found on a specific web page, as well as a preview of how that page might appear in Google search results. Learn more.